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From Maciej Miklas <mac.mik...@googlemail.com>
Subject Re: Cassandra 1.x and proper JNA setup
Date Fri, 04 Nov 2011 07:50:16 GMT
Super - thank you for help :)

On Thu, Nov 3, 2011 at 6:55 PM, Jonathan Ellis <jbellis@gmail.com> wrote:

> Relying on that was always a terrible idea because you could easily
> OOM before it could help.  There's no substitute for "don't make the
> caches too large" in the first place.
>
> We're working on https://issues.apache.org/jira/browse/CASSANDRA-3143
> to make cache sizing easier.
>
> On Thu, Nov 3, 2011 at 3:16 AM, Maciej Miklas <mac.miklas@googlemail.com>
> wrote:
> > According to source code, JNA is being used to call malloc and free. In
> this
> > case each cached row will be serialized into RAM.
> > We must be really careful when defining cache size - to large size would
> > cause out of memory. Previous Cassandra releases has logic that would
> > decrease cache size if heap is low.
> > Currently each row will be serialized without any memory limit checks -
> > assuming that I understood it right.
> >
> > Those properties:
> >    reduce_cache_sizes_at: 0.85
> >    reduce_cache_capacity_to: 0.6
> > are not used anymore - at least not when JNA is enabled, witch is default
> > from Cassandra 1.0
> >
> >
> > On Wed, Nov 2, 2011 at 1:53 PM, Maciej Miklas <mac.miklas@googlemail.com
> >
> > wrote:
> >>
> >> I've just found, that JNA will be not used from 1.1 release -
> >> https://issues.apache.org/jira/browse/CASSANDRA-3271
> >> I would be also nice to know what was the reason for this decision.
> >>
> >> Regards,
> >> Maciej
> >>
> >> On Wed, Nov 2, 2011 at 1:34 PM, Viktor Jevdokimov
> >> <Viktor.Jevdokimov@adform.com> wrote:
> >>>
> >>> Up, also interested in answers to questions below.
> >>>
> >>>
> >>> Best regards/ Pagarbiai
> >>>
> >>> Viktor Jevdokimov
> >>> Senior Developer
> >>>
> >>> Email: Viktor.Jevdokimov@adform.com
> >>> Phone: +370 5 212 3063
> >>> Fax: +370 5 261 0453
> >>>
> >>> J. Jasinskio 16C,
> >>> LT-01112 Vilnius,
> >>> Lithuania
> >>>
> >>>
> >>>
> >>> Disclaimer: The information contained in this message and attachments
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> >>> irrevocably delete this message and any copies.-----Original
> Message-----
> >>> From: Maciej Miklas [mailto:mac.miklas@googlemail.com]
> >>> Sent: Tuesday, November 01, 2011 11:15
> >>> To: user@cassandra.apache.org
> >>> Subject: Cassandra 1.x and proper JNA setup
> >>>
> >>> Hi all,
> >>>
> >>> is there any documentation about proper JNA configuration?
> >>>
> >>> I do not understand few things:
> >>>
> >>> 1) Does JNA use JVM heap settings?
> >>>
> >>> 2) Do I need to decrease max heap size while using JNA?
> >>>
> >>> 3) How do I limit RAM allocated by JNA?
> >>>
> >>> 4) Where can I see / monitor row cache size?
> >>>
> >>> 5) I've configured JNA just for test on my dev computer and so far I've
> >>> noticed serious performance issues (high cpu usage on heavy write
> load), so
> >>> I must be doing something wrong.... I've just copied JNA jars into
> >>> Cassandra/lib, without installing any native libs. This should not
> work at
> >>> all, right?
> >>>
> >>> Thanks,
> >>> Maciej
> >>>
> >>
> >
> >
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com
>

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